The present invention relates to an evaporative humidifier having a removable indicator for indicating when a wick element requires replacement and/or a water supply requires refilling. More particularly, the present invention relates to a modular indicator that is removably attached to an air outlet grill of a humidifier for monitoring the performance of the humidifier.
Humidifiers are useful in raising the humidity of air inside homes, particularly during periods of dry weather during the winter and heat inside a home causes the relative humidity within the home to be lowered to an uncomfortable level. Under these circumstances, it is beneficial to introduce moisture into the air. Several types of humidifiers for increasing humidity in a room are well known in the art, and include steam-type, ultrasonic, warm-air and evaporative humidifiers.
Certain humidifiers, and in particular the evaporative type, generally include a housing having an inlet, an outlet, and a reservoir for holding water, a water absorbing material seated partially submerged in the water of the reservoir, and a fan that is connected to the housing for creating an airflow. The water absorbing material is generally known as a wick in the art and is adapted to draw water in the upper nonimmersed part by capillary action. The airflow created by the fan is directed to pass through the upper non-immersed portion of the wick to humidify the air in the room.
A problem associated with humidifiers that utilize wicks is that they tend to accumulate minerals from the water which blocks the capillary action of the wick. Accordingly, the performance of the wick degrades over time requiring replacement.
It is difficult to determine when a wick requires replacement by physical inspection or by monitoring the period of actual use. This is because both of these methods do not assess the actual performance of the wick. The wick will change color as a result of the absorption of various minerals over a period of a time. Since the minerals that exist in public water supplies vary from one municipality to another, practical replacement guidelines based only on a physical inspection and monitoring the length of use are not practical.
Commonly assigned U.S. Pat. No. 5,800,741 to Glenn et al. discloses an evaporative humidifier having a wick filter with color change indicator. The wick change indicator disclosed therein was premised upon a color change indicator that would change color after a period of use. As noted in the specification at Column 9, Lines 45-53, although the life of the wick filter is estimated to be approximately 6 weeks, the water supply can have an adverse effect on the color change indicator disclosed therein.
It is an object of the present invention to provide a humidifier with a removable humidifier performance indicator.
It is a further object of the present invention to provide a modular indicator that is removably attached to an air outlet grill of a humidifier for monitoring the performance of the humidifier to assess whether the humidifier wick requires replacement and/or the humidifier water supply requires refilling.
It is yet another object of the present invention to provide a modular indicator hat is inexpensive and easy to manufacture.
In accordance with one form of the present invention, a humidifier includes a housing having an air inlet, an air outlet and a reservoir for holding water. The reservoir supports a wick, which is seated therein. A fan is provided within the housing for creating an airflow. The airflow enters the air inlet, passes through the wick for adding moisture to the air and exits through the air outlet. The exiting air has an exit-relative humidity associated therewith. The humidifier further includes a wick change indicator removably attached to the air outlet. The wick change indicator includes a humidity sensing means, such as a hygrometer, positioned within the airflow for measuring the exit-relative humidity of the airflow and a display coupled to the humidity sensing means for indicating when the wick requires replacement based upon the measured exit-relative humidity reaching a predetermined value.
In a preferred embodiment of the present invention, the hygrometer has a humidity sensitive element, which is coupled to an indicating needle providing a visual display that the wick requires replacement. Preferably the humidity sensitive element is a metallic coil. The display includes markings such that the needle is positioned with respect to the markings to provide an indication that the wick needs replacement and/or the reservoir is empty.
In an alternative embodiment of the present invention, the hygrometer is provided as a chemically impregnated label. The label changes color as a function of humidity. The label has a first region that is light in color and darkens when the exit-relative humidity of the airflow reaches a first predetermined value. The label also has a second region that is light in color and darkens when the exit-relative humidity of the airflow reaches a second predetermined value.
In another embodiment of the present invention, the hygrometer is provided in the form of an electrical-type hygrometer, e.g. a resistive or capacitive element whose value varies as a function of sensed humidity, and the display is a liquid crystal type calibrated to indicate that the wick requires replacement when the exit-relative humidity of the airflow falls below a predetermined humidity.
In still a further embodiment of the present invention, the modular wick change indicator includes a second hygrometer that measures the ambient-relative humidity. The wick change indicator has a means for comparing the exit-relative humidity with the ambient-relative humidity for indicating when the wick requires replacement.
Preferably, the air outlet includes a grill and the wick change indicator includes an attachment member for removably attaching the wick change indicator to the grill of the air outlet. The attachment member includes at least one finger projecting outwardly from the wick change indicator for engagement with the grill. In a preferred embodiment, the attachment member includes at least one straight finger projecting outwardly from the wick change indicator and at least one resilient finger projecting outwardly from the wick change indicator at an angle with respect to the straight finger. The at least one straight finger and the at least one resilient finger form an open resilient jaw for frictionally holding at least one slat forming the grill. The modular wick change indicator further preferably includes a retaining ring and a transparent cover attached to the retaining ring for housing the hygrometer and the display therein.
In another alternative embodiment of the present invention, a modular indicator is provided for indicating the need to refill a water supply to a room humidifier. The room humidifier is of the type having an air outlet for providing a flow of air having an exit-relative humidity associated therewith into a room having an ambient-relative humidity. The indicator includes a humidity sensing means positioned within the airflow for measuring the exit-relative humidity of the airflow, a display coupled to the humidity sensing means for indicating when the water supply needs refilling based upon the measured exit-relative humidity substantially reaching a predetermined value and an attachment member for removably attaching the indicator to the air outlet.
In a method for determining when a wick element of a humidifier requires replacement, a wick change indicator having a humidity sensing means and a display coupled to the humidity sensing means is attached to the air outlet of the humidifier. The exit-relative humidity of the flow of air from the air outlet of the humidifier is sensed with the humidity sensing means of the wick change indicator and the display indicates when a predetermined humidity level has been substantially reached to indicate that the wick element should be replaced.
In a method for determining when a water supply of a humidifier requires refilling, an indicator having a humidity sensing means and a display coupled to the humidity sensing means is attached to an air outlet of the humidifier. The exit-relative humidity of the air flowing from the air outlet of the humidifier is sensed with the humidity sensing means of the indicator and the display indicates when a predetermined humidity level has been substantially reached to indicate that the water supply should be refilled.
In a method for determining when a wick element of a humidifier requires replacement or a water supply of the humidifier requires refilling, an indicator having a humidity sensing means and a display coupled to the humidity sensing means is attached to an air outlet of the humidifier. The exit-relative humidity of air flowing from the air outlet of the humidifier is sensed with the humidity sensing means of the indicator and the display indicates when a predetermined humidity level has been substantially reached to indicate that either the wick element should be replaced or the water supply should be refilled.
A preferred form of the humidifier and the removably attachable humidifier performance indicator of the present invention, as well as other embodiments, objects, features and advantages of this invention will be apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.